Could I ask the forums help in identifying a leather HP pouch I picked up the other day.

I have searched Google, including images and cannot find any reference to it. It's 5.5x10x1 inches with a Velcro fold-over flap. The flap has the HP / HEWLETT PACKARD logo pressed into the leather. It's all black, and has a soft black interior. There is a small white seam label which says Made in Singapore.

I've found a couple of cases at the flea that were made out of the same material, had the same label, and were about that height but wider.
Because of what I found them with; I believer mine were cable pouches for hp laptop or printer gear (cables?). I turned them inside out and with two seams each to narrow them up they became good homes for naked calcs. Yours looks like it has a factory seam.
As Forrest Gump said: "that's all I know about that".